[srslte-users] srsenb log and uplink mcs control

[Nicola Bui]

Dear SRS,

I was testing srsENB with a commercial mobile phone trying to fix the MCS
used in the communication, while I found a couple of problems:
1) the output of the PHY log of srsenb is not correctly aligned
2) setting pusch_mcs in the configuration file does not work

Concerning the first I am reporting below three lines from the log file of
the enb when I configured pusch_mcs = 5
11:30:54.070496 [MAC ] [I] [06649] SCHED: UL tx rnti=0x46, pid=1, dci=3,8,
grant=(0,25), n_rtx=0, tbs=501, bsr=0 (512-501)
11:30:54.070515 [PHY1] [I] [06641] PDCCH: UL DCI Format0  rnti=0x46,
cce_index=8, L=8, tpc=1, tti_tx_dl=6645
11:30:54.078372 [PHY1] [I] [06649] PUSCH: rnti=0x46, prb=(0,0), tbs=25,
mcs=549, idx=10, rv=0, snr=31.3 dB, n_iter=1, crc=OK, dec_time=  67 us
The first line is related to the MAC layer which schedules an uplink
transmission for RNTI 0x46 using 25 resource blocks and a transport block
size of 501 bytes
The third line is the PHY layer log of the same transmission, which
correctly report the RNTI, but, starting from tbs, all values are shifted
of 1 position to the right (e.g., mcs cannot be 549,, but should be the
next value, 10)
>From this last information I also understand that, even though I set
pusch_mcs=5 the uplink transmission of the device is scheduled at MCS=10.

I don't mind about the log misalignment, I can script a workaround to read
the correct value, but I really like to test the mobile phone communication
at fixed MCS on both uplink and downlink. Note that using pdsch_mcs
correctly fix all downlink coommunications to the desired MCS. Is there
anything I can do to fix this?

Thanks,
Nicola
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